We studied the effect of the topical instillation of phenylephrine hydrochloride on accommodation. Factors considered were iris color and the influence of the prior application of a topical anesthetic. There has been controversy concerning the role of the sympathetic nervous system in accommodation. Our results indicate that the sympathetic nervous system does influence accommodation. Prior application of an anesthetic prolongs the effect of phenylephrine on the accommodation and on pupil diameter in eyes with either lightly or more heavily pigmented irides.